Method of manufacturing carbons



(No Model.)

P. P. NUNGESSER. METHOD OF MANUFAGTURING-GARBONS.

No. 409,490. Patented Aug. 20, 1889.

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.PHILIP l). NUNGESSER, OF CLEVELAND, OHIO.

METHOD OF MANUFACTURING CARBONS.

SPECIFICATION forming part of Letters Patent No. 409,490, dated August20, 18819.

Application filed January 3l, 1889. Serial No. 298,255. (No model.)

To @ZZ whom t may concern.-

Be it known that I, PHILIP P. NUNGnssER, of Cleveland, in the county ofCuyahoga and State of Ohio, have invented anew and useful Improvement inthe Method of Manufacturing Carbons; and I do hereby declare that thefollowing is a full, clear, and eXact description of the same.

My invention is an improved method of manufacturing carbon electrodesused in arc lamps.

The object of my invention is to lessen the percentage of loss whichattends the method of manufacturing carbons noWin use, to perform theWork of carbonization more rapidly than has heretofore been done, and toimprove the quality of the carbons in respect to form, and to renderthem uniform in quality.

My invention consists, first, in packing the carbons in saggers ofgreater depth than the length of the carbons, covering the ends of thecarbons with sand, and passing the saggers thus packed through aheating-chamber in which the highest degree of heat is at the dischargeend and the lowest degree at the charging end.

It consists, in the second place, in packing the carbons in saggersWhich contain small charges, in moving these saggers through a heatedchamber the heat of which gradually increases from the charging to thedischarge end, and finally removing each sagger While hot, When it haspassed through the chamber, and emptying its carbonized contents.

Thirdly, my invention consists in packing the carbons in verticalposition Within the saggers on the bottom thereof, passing the saggerssuccessively through a heated chamber from a lower to a highertemperature with the open end upward, with the iiame passing over theupper ends of the saggers, whereby the carbons are dried and carbonizedby graduallyincreased heat from the top downward, substantially ashereinafter explained.

In the manufacture of carbons as heretofore practiced it has beencustomary to pack the carbons in a green state and in saggers, and toplace the saggers thus packed within a furnace the temperature of whichis subsequently raised to a sufficient degree to produce carbonization,after Which the furnace heat is allowed to subside and the saggersremoved.

In this method there is difliculty in grading properly the increase ofheat for the perfect formation of the carbons. The material of whichthey are composed includes substances which under increased temperaturesgive forth vapors, an d Where the temperature is too rapidly raisedthese vapors are generated more rapidly than they can pass off from thecarbons without disturbance of its interior substance, and thus mar thetexture or density which the carbon has received from its cmpression.Further, in the furnace the carbons are variably affected by reason oftheir differentpositions in respect to the heat generated in theiire-chamber-that is to say, carbons from one part of the furnace differin quality or extent of carbonization as compared With carbons inanother part, and this inequality seriously affects the utility of thecarbon in electric lighting. Iiurthermore, in the furnace heretoforeused the application of heat vin respect to the position of the carbonshas been such that it has been difficult to prevent warping, and thepercentage of carbons damaged by Warping and change of texture ordensity by the too-rapid escape of the vapors has materially increasedthe cost of producing the carbons.

I have sought by the invention hereinafter explained to avoid thesespecial dilculties, and thus to obtain the objects sought to beaccomplished.

The apparatus which I have found best for carrying out my invention isshown in the accompanying drawings, but is npt herein claimed, as it isthe subject of an application iiled inthe United States Patent Office onthe 27th of December, 1388, Serial No. 294,790. In this figure the lirebox or chamberis represented at a, the heating-ch amber at B, thecharging end at C, and the receptacle or sagger for the carbons at I). Iprefer to use a receptacle substantially the same as that shown, so thatthe carbons are subjected to the heat of the furnace in smallquantities, and are thus thoroughly carbonized, each charge beingadapted by this means to be affected by the heat of the furnace upon thetop and every side. The heat from the nre-chamber passes over thefire-bridge, Where it' meets a current of air, and this produces moreperfect combustion and makes a white heat in the furnace IOO inproximity to the iire-bridge, gradually decreasing -as it approaches thecharging end in substantially the proportions which I have indicated onthe drawings in Fig. l., in which I have represented the varyingtemperatures throughout the extent of the heating-chamber When thetemperature adjoins the lirebridge as at about 3,000o Fahrenheit. Itwill be understood, however, that this is only an approximate scale, andit may be made to vary by regulation of dampers which maybe inconnection with different parts of the heating-chamber. The proportionswhich I have indicated show the temperature at which the furnace hasbeen worked practically.

I have not limited myself in respect to the size of the apparatus. Itslateral and vertical dimensions are made to suit the size of the caseswhich hold the carbons. A good working length of the apparatus isbetween fifty and one hundred feet. It will thus be seen that inplacing' the carbons in the charging end they are subjected to thelowest temperature, and as they are moved slowly through the entirelength of the furnace they are subjected to increasing temperature,which first dries them, and, by reason of the charges being separatedfrom each other, the heat penetrates from every side, and when thereceptacles have reached the end nearest the fire-bridge the carbonswill be found to have been thoroughly carbonized and to be ready forremoval. By packing the carbons verticallyfin receptacles nodisplacement is caused and there can be no rupture nor bending of thecarbons7 and when they are removed and taken from the receptacles theywill be found to be perfectly straight and true.

In carrrying out my invention by the apparatus above described I iirstplace the carbons in the saggers, preferably while they are lying inhorizontal position, by introducing them through the-open top, withtheir ends resting against the bottom. lVhen the saggers have beenfilled, there is a space between the upper ends of the carbons and themouth of the saggers, which is preferably lled with sand, and all thesaggers to be used in the furnace are prepared in this manner. Thefurnace is then heated by fire in the iirechamber, and the passage ofthe products of combustion over the bridge and through the length of thechamber is regulated by openings, so that the heat diminishes in properdegrees, which may be observed by the gages placed in differentpositions throughout the length of the chamber. The chamber being thusprepared, the saggers containing the charges are introduced successivelyand pass slowly from the charging end (which is the end of least heat)toward the discharging or hottest end of the chamber. As the chargespass, as shown in the drawings, they are three abreast and the saggersnearly ll the space in the chamber from side to side, but leave a spaceover the top for the passage of the products of combustion whichnaturally rise, aud thus the pencils are heated from the top downward ina gradual degree, which causes the gradual evaporation from their upperends, and as they rest upon the lower ends there is no tendency to warp.Further, as they are moved slowly and subjected to a gradual increase ofheat regulated to a proper degree, the vapors are slowly generatedwithin the carbon, and at such a degree that they escape withoutexpansion of the carbons or rupture, or in any way diminishing theirsolidity or texture. the saggers are removed and emptied, and as theconstruction of the furnace admits their complete removal from thefurnace while they are hot, another advantage arises, whereby a savingis effected in respect to the saggers.

In the old process, heretofore referred to, the saggers withtheircharges must cool before they can be removed, and as they shrinkwith the charges unremoved they are liable to crack, and in practicemany of them do crack and are ruined, which involves a considerableloss. In the furnace and method above described by me saggers may beremoved and emptied while they are hot, and, shrinking in the emptiedcondition, there is little liability of cracking, and the same saggersmay be used many times.

I am aware that prior to my invention it has been suggested to bakebricks by passing them loaded on cars through an elongatedheatingchamber in which the temperature was lowest at the charging endand greatest near the furnace, the cars passing from the heatingchamberinto a cooling-chamber; but in this case the bricks were simply piledupon the cars and exposed to the direct action of the heat and air. Inthe baking of carbons, however, as is well known, they are subjected tosuch intense heat that were they exposed in their transmission throughthe heating-chamber they would be entirely consumed, being composed of acombustible material. Heretofore in the baking of carbons the carbonsare placed in saggers, which they completely fill, and these are placedside by side or in layers, and the whole covered with sand and tiles.This is-impracticable where the saggers are to be moved, and in order torender it possible to move the saggers and at the same time to mufe themI provide saggers of slightly greater depth than the length of thecarbons, in which the carbons are packed closely and their ends coveredby sand; and in the passage of the carbons through the heating-chamberthey are thoroughly carbonized, while at the same time muflied by thewalls of the saggers and the covering of sand, so as to prevent theaccess of air to the carbons and the consequent injurious effect.

I claim as my inventionl. The hereinbefore-described method of treatingcarbons, consisting in packing them in saggers of greater depth than thelength At the discharge end n IOO IIO

of the carbous, covering the ends of the carbons with sand7 and passingthe saggers thus packed through a heating-chamber in which the highestdegree of heat is at the discharge end and the lowest degree at thecharging end, substantially as described.

2. The described method of baking carbons, consisting in placing thecarbons in saggers, passing the sag-gers successively thro ugh a chamberfrom a lower to a higher heat, and finally removing` the saggers whilehot from the discharge end of the chamber, substantially as described.

3. The described method of treating carbons, consisting in placing themin saggers witln the ends resting on the bottom of the

